org.parboiled.transform.RuleMethodInterpreter Maven / Gradle / Ivy

Go to download
/*
 * Copyright (c) 2009-2010 Ken Wenzel and Mathias Doenitz
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package org.parboiled.transform;

import com.google.common.base.Preconditions;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.analysis.AnalyzerException;
import org.objectweb.asm.tree.analysis.BasicInterpreter;
import org.objectweb.asm.tree.analysis.BasicValue;
import org.parboiled.Rule;
import org.parboiled.support.Checks;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public final class RuleMethodInterpreter
    extends BasicInterpreter
{
    private final RuleMethod method;
    private final List additionalEdges = new ArrayList<>();

    public RuleMethodInterpreter(final RuleMethod method)
    {
        this.method = method;
    }

    @Override
    public BasicValue newValue(final Type type)
    {
        BasicValue basicValue = super.newValue(type);
        if (basicValue == BasicValue.REFERENCE_VALUE)
            // record the exact type and not just "Ljava/lang/Object"
            basicValue = new BasicValue(type);

        return basicValue;
    }

    @Override
    public BasicValue newOperation(final AbstractInsnNode insn)
        throws AnalyzerException
    {
        return createNode(insn, super.newOperation(insn));
    }

    @Override
    public BasicValue copyOperation(final AbstractInsnNode insn,
        final BasicValue value)
        throws AnalyzerException
    {
        return createNode(insn, super.copyOperation(insn, value), value);
    }

    @Override
    public BasicValue unaryOperation(final AbstractInsnNode insn,
        final BasicValue value)
        throws AnalyzerException
    {
        return createNode(insn, super.unaryOperation(insn, null), value);
    }

    @Override
    public BasicValue binaryOperation(final AbstractInsnNode insn,
        final BasicValue value1, final BasicValue value2)
        throws AnalyzerException
    {
        return createNode(insn, super.binaryOperation(insn, null, null), value1,
            value2);
    }

    @Override
    public BasicValue ternaryOperation(final AbstractInsnNode insn,
        final BasicValue v1, final BasicValue v2, final BasicValue v3)
        throws AnalyzerException
    {
        // this method is only called for xASTORE instructions, parameter v1 is
        // the value corresponding to the NEWARRAY, ANEWARRAY or MULTIANEWARRAY
        // instruction having created the array, we need to insert a special
        // dependency edge from the array creator to this xSTORE instruction
        additionalEdges.add(new Edge(insn, findArrayCreatorPredecessor(v1)));
        return createNode(insn, super.ternaryOperation(insn, null, null, null),
            v1, v2, v3);
    }

    @Override
    public BasicValue naryOperation(final AbstractInsnNode insn,
        final List values)
        throws AnalyzerException
    {
        return createNode(insn, super.naryOperation(insn, null),
            (BasicValue[]) values.toArray(new BasicValue[values.size()]));
    }

    @Override
    public void returnOperation(final AbstractInsnNode insn,
        final BasicValue value, final BasicValue expected)
        throws AnalyzerException
    {
        Preconditions.checkState(insn.getOpcode() == ARETURN);
        Preconditions.checkState(unwrap(value).getType().equals(
            Type.getType(Rule.class)));
        Preconditions.checkState(unwrap(expected).getType().equals(
            Type.getType(Rule.class)));
        Preconditions.checkState(method.getReturnInstructionNode() == null);
        method.setReturnInstructionNode(createNode(insn, null, value));
    }

    private InstructionGraphNode createNode(final AbstractInsnNode insn,
        final BasicValue resultValue, final BasicValue... prevNodes)
    {
        return method.setGraphNode(insn, unwrap(resultValue), Arrays.asList(
            prevNodes));
    }

    @Override
    public BasicValue merge(final BasicValue v, final BasicValue w)
    {
        // we don't actually merge values but use the control flow detection to
        // deal with conditionals
        return v;
    }

    public void newControlFlowEdge(final int instructionIndex,
        final int successorIndex)
    {
        final AbstractInsnNode fromInsn
            = method.instructions.get(instructionIndex);
        final AbstractInsnNode toInsn = method.instructions.get(successorIndex);
        if (isLabelOrJump(fromInsn) || isLabelOrJump(toInsn))
            additionalEdges.add(new Edge(fromInsn, toInsn));

    }

    private static boolean isLabelOrJump(final AbstractInsnNode node)
    {
        return node.getType() == AbstractInsnNode.LABEL
            || node.getType() == AbstractInsnNode.JUMP_INSN;
    }

    private AbstractInsnNode findArrayCreatorPredecessor(final BasicValue value)
    {
        final String errorMessage = "Internal error during analysis of rule" +
            " method '" + method.name + "', please report this error to" +
            " https://github.com/parboiled1/grappa/issues! Thank you!";
        Checks.ensure(value instanceof InstructionGraphNode, errorMessage);
        InstructionGraphNode node = (InstructionGraphNode) value;
        while (true) {
            final int opcode = node.getInstruction().getOpcode();
            if (opcode == ANEWARRAY || opcode == NEWARRAY
                || opcode == MULTIANEWARRAY)
                break;
            Checks.ensure(node.getPredecessors().size() == 1, errorMessage);
            node = node.getPredecessors().get(0);
        }
        return node.getInstruction();
    }

    public void finish()
    {
        // add all edges so far not included
        for (final Edge edge : additionalEdges) {
            InstructionGraphNode node = getGraphNode(edge.from);
            if (node == null)
                node = createNode(edge.from, null);
            InstructionGraphNode succ = getGraphNode(edge.to);
            if (succ == null)
                succ = createNode(edge.to, null);
            succ.addPredecessor(node);
        }
    }

    private InstructionGraphNode getGraphNode(final AbstractInsnNode insn)
    {
        return method.getGraphNodes().get(method.instructions.indexOf(insn));
    }

    private static BasicValue unwrap(final BasicValue resultValue)
    {
        return resultValue instanceof InstructionGraphNode
            ? ((InstructionGraphNode) resultValue).getResultValue()
            : resultValue;
    }

    private static final class Edge
    {
        private final AbstractInsnNode from;
        private final AbstractInsnNode to;

        private Edge(final AbstractInsnNode from, final AbstractInsnNode to)
        {
            this.from = from;
            this.to = to;
        }
    }
}